In the state of the art, a number of printers arranged to be manually placed on an image receiving medium are known. The printing means of the printer or the entire printer is operable to scan over the image receiving medium in the printing operation. Thus, the medium is not fed through the printer--as in most office sheet printers, but the printer is placed upon the medium.
Such a printer is known from EP 564297-A. The printer has an ink jet print head which is scanning in two orthogonal directions over the image receiving medium, onto which the printer is placed manually. The printer is connected to a computer and capable e.g. of printing addresses onto envelopes, but can also be used separately from the computer for printing data downloaded from the computer to the printer.
Another ink jet printer to be placed on a printing medium is disclosed in U.S. Pat. No. 5,634,730 A. This printer is provided with a keyboard for data inputting, but can also print images downloaded from a computer. The print head scans over the image receiving medium along a special path, e.g. helically or like a pendulum. It can print data downloaded from a computer or one of a set of predetermined words such as "PAID" etc.
DE 3142937-A refers to a so-called hand stamp which is placed manually on the image receiving medium. It can print data downloaded from an accounting machine, or images consisting of user-selected fixed phrases. The hand stamp has a thermal print head and an ink ribbon for printing.
The printers known in the prior art are thus capable of printing an image onto an image receiving medium, and make use of a scanning print head. Printing is performed in two steps: the first one is alignment of the printer on the image receiving medium such that the image can be printed in the desired position and the second step is printing. However, although the printers can communicate with a computer to receive data to be printed, that is the limit of their interaction. There is no other active cooperation between the printer unit and a computer.